The plant you put in a pot I prepared outside (10)
I believe the answer is:
poinsettia
'the plant you' is the definition.
The definition suggests a singular noun which matches the answer.
'put in a pot i prepared outside' is the wordplay.
'put in' becomes 'inset' (insetting is a kind of putting in).
'prepared' indicates anagramming the letters.
'outside' means one lot of letters goes inside another.
'a'+'pot'+'i'='apoti'
'apoti' with letters rearranged gives 'potia'.
'inset' put inside 'potia' is 'POINSETTIA'.
Can you help me to learn more?
(Other definitions for poinsettia that I've seen before include "bloom" , "Flower popular at Christmas" , "Plant with showy bracts, usu. red, pink or white" , "Shrub often given at Christmas" , "poisonous bush" .)